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  1. import java.util.HashMap;
  2. import java.util.Map;
  3.  
  4. public class Main {
  5.  
  6.     public static HashMap<Long, Long> primeFactors(long n) {
  7.         HashMap<Long, Long> factorCount = new HashMap<>();
  8.  
  9.         while (n % 2 == 0) {
  10.             factorCount.put(2L, factorCount.getOrDefault(2L, 0L) + 1);
  11.             n /= 2;
  12.         }
  13.  
  14.         for (long i = 3; i <= Math.sqrt(n); i += 2) {
  15.             while (n % i == 0) {
  16.                 factorCount.put(i, factorCount.getOrDefault(i, 0L) + 1);
  17.                 n /= i;
  18.             }
  19.         }
  20.  
  21.         if (n > 2) {
  22.             factorCount.put(n, factorCount.getOrDefault(n, 0L) + 1);
  23.         }
  24.  
  25.         return factorCount;
  26.     }
  27.  
  28.     public static void main(String[] args) {
  29.         long n =50;
  30.         HashMap<Long, Long> factors = primeFactors(n);
  31.  
  32.         for (Map.Entry<Long, Long> entry : factors.entrySet()) {
  33.             System.out.println(entry.getKey() + " ^ " + entry.getValue());
  34.         }
  35.     }
  36. }
  37.  
Success #stdin #stdout 0.15s 57712KB
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2 ^ 1
5 ^ 2
https://ideone.com/2OMkmD
language:
Java (HotSpot 12)
created:
1 hour ago
visibility:
public

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